A representation of an object that resembles the original. Analog devices monitor conditions, such as movement, temperature and sound, and convert them into analogous electronic or mechanical patterns. For example, an analog watch represents the planet's rotation with the rotating hands on the watch face. Telephones turn voice vibrations into electrical vibrations of the same shape. Analog implies a continuous signal in contrast with digital, which breaks everything into numbers. Video cameras scan their viewing area a line at a time and convert the infinitely varying intensities of red, green and blue (RGB) light into analogous electrical signals. See sampling.
Advantages/Disadvantages of Analog Recording
Audio and video transmission has been analog since the beginning of radio and TV and the first magnetic recording. While the industry is increasingly digital, analog is still widely used in both commercial and home environments (audio cassettes, VHS tapes, commercial video, radio and TV broadcasting).
The ability to capture the subtle nature of the real world is the single advantage of analog techniques. It takes ever increasing digital capacities and bandwidth to match the granularity of analog systems.
Digital Means Perfect Replication
Once recorded, analog equipment, no matter how modern, cannot copy signals perfectly. Third and fourth generations of analog audio and video recordings show marked deterioration.
By recording in digital from the beginning, or by converting from analog to digital at an early stage, audio and video data can be preserved indefinitely and copied over and over without deterioration. This fact has caused publishers of digital media much anguish (see copyright, DRM and peer-to-peer network) and has always been a problem for software publishers since the first computer programs were made available for sale.
Analog Concepts
There are many analog systems. Watch hands are analogous to the earth's rotation. Analog telephones turn air waves into analogous electrical waves.
Analog Radio
In traditional radio, the original sound waves are maintained as analogous electrical waves throughout the entire chain from recording microphone to the listener's speakers. The analog waves are transmitted over the air in the radio station's channel frequency, which is called a "carrier." The carrier is altered (modulated) to contain the analog waves as if wrapped within conceptually.
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